An Etymological Dictionary of Astronomy and Astrophysics

Geology: The various processes, such as the actions of wind, rain, temperature changes and so forth, which mechanically and chemically cause exposed rocks to decompose.

Etymology (EN): From → weather + → -ing.

Etymology (PE): Sâyand, from sâyidan “to touch, to rub,” variants sâbidan, pasâvidan;
Khotanese sauy- “to rub;” Sogdian ps’w- “to touch;” ultimately
Proto-Iranian *sau- “to rub.”